Air conditioner and controlling method thereof

ABSTRACT

An air conditioning system includes an indoor heat exchange unit which exchanges heat with indoor air, and an outdoor heat exchange unit which exchanges heat with outdoor air. The outdoor heat exchange unit performs a defrosting operation to remove frost from the outdoor heat exchange unit while the indoor heat exchange unit simultaneously performs a heating operation to heat the indoor air.

This application claims the benefit of Korean Application No. 10-2006-0073434, filed on Aug. 3, 2006, which is hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to an air conditioning system and a controlling method thereof.

Generally, an air conditioning system is an apparatus for heating/cooling an indoor space using a refrigerant cycle.

The air conditioning system provides high temperature refrigerant compressed by a compressing unit to an indoor heat exchanger to heat an indoor space. Refrigerant condensed at the indoor heat exchanger expands and then is provided to an outdoor heat exchange unit. Refrigerant evaporated at the outdoor heat exchange unit flows into a compressing unit. At this point, when outdoor temperature is low, humidity contained in air is frozen on the surface of the outdoor heat exchange unit. When a large amount of frost is generated on the surface of the outdoor heat exchange unit, the heat exchange performance of the outdoor heat exchange unit is considerably reduced, and efficiency of a refrigerant cycle is considerably reduced on the whole. Therefore, a defrosting operation is performed to remove frost generated on the outdoor heat exchange unit. During the defrosting operation, refrigerant circulates in an opposite direction to the direction of a heating operation.

However, since the air conditioning system circulates refrigerant in an opposite direction to a direction of the heating operation during the defrosting operation, the air conditioning system has not been able to heat an indoor space during the defrosting operation. Also, since cooling air is supplied to the indoor space during the defrosting operation, consumers have felt unpleasant feeling. Also, since the indoor space that has been heated is cooled again, heating energy has been lost.

SUMMARY

Embodiments provide an air conditioner capable of performing a heating operation even while a defrosting operation is performed.

Embodiments also provide an air conditioner capable of reducing unpleasant feeling of consumers and preventing heating energy loss.

In one embodiment, an air conditioning system includes an indoor heat exchange unit which exchanges heat with indoor air, and an outdoor heat exchange unit which exchanges heat with outdoor air, where the outdoor heat exchange unit performs a defrosting operation to remove frost from the outdoor heat exchange unit while the indoor heat exchange unit simultaneously performs a heating operation to heat the indoor air.

The air conditioning system may also include a compressing unit that discharges high temperature refrigerant, a switching unit connected to a discharge side of the compressing unit, the outdoor heat exchange unit being connected to the switching unit, an expansion unit connected to the outdoor heat exchange unit, the indoor heat exchange unit being connected to the expansion unit and the switching unit, and a bypass unit that provides the high temperature refrigerant discharged from the compressing unit to an intake side of the outdoor heat exchange unit during the defrosting operation.

The bypass unit may be connected to a refrigerant pipe between the compressing unit and the switching unit, and may be connected to a refrigerant pipe between the switching unit and the indoor heat exchange unit.

The air conditioning system may also include a connecting unit that provides refrigerant from a discharge side of the expansion unit to a discharge side of the outdoor heat exchange unit during the defrosting operation.

An accumulator including a heating unit may be disposed at an intake side of the compressing unit.

The compressing unit may include a plurality of compressors, and the bypass unit may provide refrigerant discharged from at least one of the compressors to the intake side of the outdoor heat exchange unit during the defrosting operation.

The air conditioning system may also include a refrigerant pipe connecting the compressing unit to the switching unit, the refrigerant pipe including a valve which is closed during the defrosting operation.

The bypass unit may include a valve and a pressure controller.

A heating unit that heats refrigerant may be disposed at an intake side of the compressing unit.

In another embodiment, an air conditioning system includes a bypass unit that provides refrigerant discharged from a compressing unit to an intake side of an outdoor heat exchange unit during a defrosting operation, and a connecting unit that provides expanded refrigerant to a discharge side of the outdoor heat exchange unit during the defrosting operation.

The bypass unit may be connected to a refrigerant pipe between a switching unit and an indoor heat exchange unit, and a refrigerant pipe between an expansion unit and the outdoor heat exchange unit.

The connecting unit may be connected to a refrigerant pipe between an expansion unit and the outdoor heat exchange unit, and a refrigerant pipe between a switching unit and the outdoor heat exchange unit.

The connecting unit may be connected to a refrigerant pipe between an expansion unit and the bypass unit.

A heating unit that heats refrigerant may be disposed at an intake side of the compressing unit.

In another embodiment, a method for controlling an air conditioning system includes performing heat exchange with indoor air to heat the indoor air, and simultaneously defrosting an outdoor heat exchange unit when a defrosting operation is triggered.

Defrosting the outdoor heat exchange unit may include discharging refrigerant from a compressing unit, and providing a portion of the discharged refrigerant to an intake side of the outdoor heat exchange unit via a bypass unit.

The method may also include heating refrigerant introduced to the compressing unit.

The defrosting operation may be triggered when the temperature of the outdoor heat exchange unit is less than a predetermined temperature.

An indoor heat exchange unit may perform the heat exchange with the indoor air, and refrigerant discharged from the indoor heat exchange unit may be provided to a discharge side of the outdoor heat exchange unit via a connecting unit.

Refrigerant discharged from the indoor heat exchange unit may be prevented from flowing into an intake side of the outdoor heat exchange unit.

According to the present disclosure, an outdoor heat exchange unit can be operated to remove frost even while heating an indoor space. Furthermore, since an indoor space can be heated during a defrosting operation, complaints of consumers can be resolved and heating energy loss can be prevented.

According to the present disclosure, since temperature of refrigerant introduced to a compressing unit during a defrosting operation can be raised, temperature of refrigerant introduced to a compressing unit can be raised. Furthermore, since the temperature of refrigerant introduced to the compressing unit is raised, temperature of refrigerant discharged from the compressing unit is raised, so that heating efficiency and system efficiency can be enhanced on the whole.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a circuit diagram of an air conditioning system according to an embodiment.

FIG. 2 is a flowchart of a frost removing operating method of the air conditioning system of FIG. 1.

FIG. 3 is a P-h line graph illustrating phase change of refrigerant while the air conditioning system of FIG. 1 operates to remove frost.

FIG. 4 is a circuit diagram of an air conditioning system according to another embodiment.

FIG. 5 is a flowchart of a frost removing operating method of the air conditioning system of FIG. 4.

FIG. 6 is a P-h line graph illustrating phase change of refrigerant while the air conditioning system of FIG. 4 operates to remove frost.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. However, the present disclosure is not limited to the embodiments, but other embodiments can be easily made by adding, modifying, or deleting another elements, which may also fall within the scope of the present disclosure.

FIG. 1 is a circuit diagram of an air conditioning system according to an embodiment, FIG. 2 is a flowchart of a frost removing operating method of the air conditioning system of FIG. 1, and FIG. 3 is a P-h line graph illustrating phase change of refrigerant while the air conditioning system of FIG. 1 operates to remove frost.

Referring to FIG. 1, the air conditioning system includes a compressing unit 10. The compressing unit 10 can include a plurality of compressors 11 and 12. At this point, the compressing unit 10 includes a main compressor 11 and a subcompressor 12. The main compressor 11 operates during all operations, and the subcompressor 12 can operate only when necessary. Also, the compressing unit 10 can consist of one compressor.

Check valves 15 can be disposed at refrigerant pipes 111 on the discharge side of the compressing unit 10, respectively, to prevent refrigerant discharged from the compressing unit 10 from flowing backward.

A switching unit 20 is connected to the refrigerant pipes 111 on the discharge side of the compressing unit 10. At this point, examples of the switching unit 20 may include a 4-way valve. The switching unit 20 controls a circulating direction of refrigerant.

An indoor heat exchange unit 30 is connected to the switching unit 20. An expansion unit 40 is connected to the indoor heat exchange unit 30. Examples of the expansion unit 40 may include a linear expansion valve (LEV) and a capillary tube that expands refrigerant.

An outdoor heat exchange unit 50 is connected to the expansion unit 40. The switching unit 20 is connected to the outdoor heat exchange unit 50.

An accumulator 60 is disposed at the compressing unit 10 and a refrigerant pipe 114 on the intake side of the switching unit 20. The accumulator 60 provides only gas refrigerant of refrigerant introduced from the switching unit 20 to the compressing unit 10. The accumulator 60 can include a separate heating unit (not shown) for heating refrigerant.

A bypass unit 110 branches off from the refrigerant pipe 111 of the compressing unit 10. At this point, the bypass unit 110 can branch off from the refrigerant pipe 111 of the compressor 12 of the compressing unit 10. That is, the bypass unit 110 can branch off from the refrigerant pipe(s) 111 of one or more compressors of the plurality of compressors 11 and 12.

The bypass unit 110 can be connected to a refrigerant pipe 112 connecting the discharge side of the expansion unit 40 and the intake side of the compressing unit 10 during a heating operation. For example, the bypass unit 110 is connected between the discharge side of the expansion unit 40 and the refrigerant pipe 112 at the intake side of the outdoor heat exchange unit 50 during a heating operation.

The bypass unit 110 includes a first valve 101. At this point, in the case where bypass units 110 branch off from refrigerant pipes at the discharge sides of two or more compressors 11 and 12, respectively, the first valve 101 can be disposed at each of the bypass units 110. Examples of the first valve 101 may include an open/close valve for opening/closing the bypass unit 110.

Also, the bypass unit 110 can include a pressure controller 103 for controlling the pressure of refrigerant. The pressure controller 103 controls the pressure of refrigerant such that refrigerant discharged from the compressing unit 10 via the bypass unit 110 has pressure similar to the pressure of refrigerant that has passed through the expansion unit 40.

Also, a second valve 102 can be provided at a portion of the refrigerant pipe 111 that is located between a portion branching off from the bypass unit 110 and the switching unit 20. The second valve 102 allows refrigerant discharged from predetermined compressors 11 and 12 to be discharged to only the bypass unit 110.

An operation of an embodiment having the above-described construction will be described below. The air conditioning system can be selectively operated in a cooling or heating mode. A heating operation will be described below.

Referring to FIGS. 1 and 2, when the air conditioning system is operated in the heating mode (S11), refrigerant is compressed with high temperature and high pressure by the compressing unit 10. At this point, only the main compressor 11 can operate or both the main compressor 11 and the subcompressor 12 can operate depending on a heating capacity.

Refrigerant compressed by the compressing unit 10 is guided to the indoor heat exchange unit 30 by the switching unit 20. At this point, the first valve 101 is closed, and the second valve 102 is opened.

Heat exchange between refrigerant and indoor air is performed at the indoor heat exchange unit 30. At this point, the refrigerant that passes through the indoor heat exchange unit 30 is condensed by exchanging heat with the indoor air. Also, the indoor air that has exchanged heat with the refrigerant at the indoor heat exchange unit 30 is discharged to an indoor space to heat the indoor space.

Refrigerant discharged from the indoor heat exchange unit 30 reaches the expansion unit 40. The refrigerant is expanded to low temperature and low pressure while passing through the expansion unit 40. The expanded refrigerant flows into the outdoor heat exchange unit 50. The refrigerant of the outdoor heat exchange unit 50 absorbs heat from outside air to change into a gas state.

Refrigerant discharged from the outdoor heat exchange unit 50 flows into the switching unit 20, which performs a switching operation such that the refrigerant flows into the accumulator 60. The accumulator 60 allows only gas refrigerant to flow into the compressing unit 10.

Meanwhile, when the heating operation is performed under low outside temperature condition, humidity contained in outside air is formed on the surface of the outside heat exchange unit 50. When the humidity is frozen on the surface of the outside heat exchange unit 50, it changes into frost. At this point, since the outside heat exchange unit 50 serves as an evaporator, the frost of the outside heat exchange unit 50 hinders a heat exchange operation between the outside heat exchange unit 50 and the outside air. Also, since the temperature of the refrigerant discharged from the outside heat exchanger unit 50 is lowered, the temperature of refrigerant flowing into the compressing unit 10 is also lowered. Therefore, the temperature of refrigerant discharged from the compressing unit 10 is lowered, which reduces heating efficiency of the air conditioning system.

To prevent reduction in heating efficiency of the air conditioning system, when more than a predetermined amount of frost is formed on the outside heat exchange unit 50, a defrosting operation for melting the frost formed on the outside heat exchange unit 50 is performed. At this point, during the defrosting operation, the temperature of the outside heat exchange unit 50 is detected, and whether the detected temperature is less than a predetermined temperature is judged (S12). When the detected temperature is less than the predetermined temperature, the defrosting operation is performed.

Also, the defrosting operation can be performed when the heating operation is performed for a predetermined time. At this point, the heating operating time should be set in advance in a control unit (not shown) to correspond to each outside temperature.

When the defrosting operation starts, refrigerant discharged from the compressing unit 10 sequentially flows through the switching unit 20, the indoor heat exchange unit 30, the expansion unit 40, and the outdoor heat exchange unit 50. At this point, high temperature refrigerant discharged from the compressing unit 10 continuously flows into the indoor heat exchange unit 30 to heat an indoor space. Also, this refrigerant flowing is substantially the same as that during a heating operation.

Simultaneously, the first valve 101 is opened (S13), and the second valve 102 is closed. At this point, a portion of refrigerant from the compressing unit 10 flows along the bypass unit 110. The refrigerant flowing through the bypass unit 110 is controlled to have a predetermined pressure by the pressure controller 103. Also, an amount of refrigerant flowing into the switching unit 20 can be increased by slightly opening an opening degree of the second valve 102.

High temperature refrigerant of the bypass unit 110 flows into the refrigerant pipe 112 on the intake side of the outdoor heat exchange unit 50. At this point, the high temperature refrigerant of the bypass unit 110 mixes with low temperature refrigerant discharged from the expansion unit 40. Therefore, the mixed refrigerant in the refrigerant pipe 112 on the intake side of the outdoor heat exchange unit 50 has temperature considerably raised in comparison with the temperature of the refrigerant discharged from the expansion unit 40.

The mixed refrigerant of the refrigerant pipe 112 flows into the outdoor heat exchange unit 50. The mixed refrigerant melts frost formed on the surface of the outdoor heat exchange unit 50. At this point, the refrigerant discharged from the outdoor heat exchange unit 50 has relatively higher temperature than that of the discharged refrigerant in the heating operation. Therefore, the temperature of refrigerant is raised at the intake side of the compressing unit 10, so that the performance of the air conditioning system is enhanced on the whole.

An indoor space can be heated and simultaneously frost formed on the outdoor heat exchange unit 50 can be removed by allowing high temperature refrigerant to flow into the intake side of the outdoor heat exchange unit 50 (S14). Therefore, a heating operation does not need to be suspended in order to perform a separate defrosting operation.

In the above description, though an operation for removing frost formed on the outdoor heat exchange unit 50 is referred to as the defrosting operation, the front removing operation according to the present disclosure means an operation where a heating operation and a defrosting operation are performed simultaneously.

Referring to FIG. 3, assuming that a heating operation cycle and a defrosting cycle are ideally performed, refrigerant changes along a line of C1-C2-C3-C4-C1 during the heating operation cycle, and refrigerant changes along a line of C6-C7-C3-C5-C7 during the defrosting cycle.

At this point, a pressure at the discharge side of the compressing unit 10 becomes C1, and a pressure at the discharge side of the expansion unit 40 becomes C2 during the heating operation cycle.

On the other hand, during the defrosting cycle, a pressure at the discharge side of the compressing unit 10 becomes P1. At this point, since a portion of compressed refrigerant is bypassed to the refrigerant pipe 112 on the intake side of the outdoor heat exchange unit 50 via the bypass unit 110, the pressure of the portion of the compressed refrigerant becomes C3 while it passes through the expansion unit 40. Also, since the bypassed refrigerant mixes with refrigerant at the exit side of the expansion unit 40, the pressure of the mixed refrigerant is raised to C3, and the temperature is also raised. At this point, since the temperature at the entry side of the outdoor heat exchange unit 50 is raised in comparison with that during the heating operation, the frost formed on the surface of the outdoor heat exchange unit 50 is removed. Also, the temperature of refrigerant discharged from the outdoor heat exchange unit 50 is raised in comparison with that during the heating operation, the temperature of refrigerant at the entry side of the compressing unit 10 is also raised. Accordingly, the defrosting cycle moves upward in FIG. 3, so that efficiency of the air conditioning system is enhanced on the whole.

Next, an air conditioning system according to another embodiment will be described below.

FIG. 4 is a circuit diagram of an air conditioning system according to another embodiment, FIG. 5 is a flowchart of a frost removing operating method of the air conditioning system of FIG. 4, FIG. 6 is a P-h line graph illustrating phase change of refrigerant while the air conditioning system of FIG. 4 operates to remove frost.

Referring to FIG. 4, the air conditioning system includes a compressing unit 201 for compressing refrigerant in high pressure. A switching unit 202 is connected to the refrigerant discharge side of the compressing unit 201. Examples of the switching unit 202 include a 4-way valve.

An outdoor heat exchange unit 203, an indoor heat exchange unit 205, and an accumulator 206 are connected to the switching unit 202. The accumulator 206 is connected to the refrigerant intake side of the compressing unit 201. An expansion unit 204 is installed at a refrigerant pipe connecting the outdoor heat exchange unit 203 with the indoor heat exchange unit 205. Examples of the expansion unit 204 may include an LEV and a capillary tube.

The refrigerant pipe between the switching unit 202 and the indoor heat exchange unit 205, and the refrigerant pipe between the expansion unit 204 and the outdoor heat exchange unit 203 are connected to a bypass unit 210, which can include an open/close valve 211. Also, the bypass unit 210 can be provided with a pressure controller 212. The pressure controller 212 reduces the pressure of refrigerant such that the pressure of the refrigerant becomes similar to that of refrigerant from the expansion unit 204 when the refrigerant discharged from the compressing unit 201 flows into the refrigerant pipe between the expansion unit 204 and the outdoor heat exchange unit 203 via the bypass unit 210.

The refrigerant pipe between the expansion unit 204 and the outdoor heat exchange unit 203, and the refrigerant pipe between the switching unit 202 and the outdoor heat exchange unit 203 are connected to a connecting unit 220. At this point, the connecting unit 220 can be connected to the refrigerant pipe between the expansion unit 204 and the bypass unit 210. The connecting unit 220 can be provided with an open/close valve 221. The open/close valve 221 can be disposed at a portion where the refrigerant pipe between the expansion unit 204 and the outdoor heat exchange unit 203, and the connecting unit 220 are connected to each other. At this point, examples of the open/close valve 221 may include a 3-way valve. Also, the open/close valve 221 can be disposed at the connecting unit 220. The connecting unit 220 can be provided with a pressure controller (not shown).

A heating unit 207 can be disposed inside the accumulator 206. At this point, the heating unit 207 heats refrigerant received in the accumulator 206.

An operation of the air conditioning system having the above-described construction will be described below.

Referring to FIGS. 4 and 5, the air conditioning system is operated in a cooling or heating mode as refrigerant is circulated in one or the other direction. Refrigerant cycle during the cooling operation is opposite to that during the heating operation. Accordingly, only heating operation will be described below.

When the air conditioning system is operated in a heating mode, refrigerant compressed by the compressing unit 201 flows into the switching unit 202. The switching unit 202 performs a switching operation such that the refrigerant flows into the indoor heat exchange unit 205. At this point, the open/close valve 211 of the bypass unit 210 is closed.

Refrigerant flowing through the indoor heat exchange unit 205 exchanges heat with indoor air to heat an indoor space. At this point, the indoor heat exchange unit 203 serves as a condenser.

Refrigerant condensed by the indoor heat exchange unit 205 flows into the expansion unit 204 and is expanded with low temperature and low pressure. The expanded refrigerant flows into the outdoor heat exchange unit 203. Refrigerant of the outdoor heat exchange unit 203 exchanges heat with outside air. At this point, the outdoor heat exchange unit 203 serves as an evaporator.

Refrigerant of the outdoor heat exchange unit 203 flows into the switching unit 202. At this point, the open/close valve 221 of the connecting unit 220 is closed.

The switching unit 202 performs a switching operation such that refrigerant introduced from the outdoor heat exchange unit 203 flows into the accumulator 206. Only gas phase refrigerant of refrigerant that has flowed into the accumulator 206 flows into the compressing unit 201. At this point, the heating unit 207 of the accumulator 206 operates to heat the refrigerant of the accumulator 206. Then, the temperature of the refrigerant introduced into the compressing unit 201 is raised, so that efficiency of the heating cycle can be enhanced.

When outdoor temperature is low during a heating operation of the air conditioning system, humidity contained in air is formed on the surface of the outdoor heat exchange unit 203. At this point, when frost is formed on the outdoor heat exchange unit 203, the heat exchange performance of the outdoor heat exchange unit 203 considerably reduces.

To prevent reduction in the heating efficiency of the air conditioning system, a defrosting operation for melting frost formed on the outdoor heat exchange unit 203 is performed when more than a predetermined amount of frost is formed on the outdoor heat exchange unit 203.

At this point, during the defrosting operation, the temperature of the outside heat exchange unit 203 is detected, and whether the detected temperature is less than a predetermined temperature is judged (S22). When the detected temperature is less than the predetermined temperature, the defrosting operation is performed.

Also, the defrosting operation can be performed when the heating operation is performed for a predetermined time. At this point, the heating operating time should be set in advance in a control unit (not shown) to correspond to each outside temperature.

When the defrosting operation starts (S23), refrigerant discharged from the compressing unit 201 flows into the switching unit 202 and the indoor heat exchange unit 205. At this point, the open/close valve 211 of the bypass unit 210 is opened (S24).

At this point, a portion of refrigerant discharged from the switching unit 202 flows into the intake side of the outdoor heat exchange unit 203 via the bypass unit 210 to remove frost formed on the outdoor heat exchange unit 203 (S23).

Simultaneously, a portion of refrigerant discharged from the switching unit 202 flows into the indoor heat exchange unit 205. At this point, the high temperature refrigerant of the indoor heat exchange unit 205 heat an indoor space.

Refrigerant discharged from the indoor heat exchange unit 205 sequentially flows into the expansion unit 204. At this point, the valve 221 of the connecting unit 220 is switched such that refrigerant discharged from the expansion unit 204 flows to the discharge side of the outdoor heat exchange unit 203 (S25). At this point, the refrigerant discharged from the outside heat exchange unit 203 mixes with expanded refrigerant flowing through the connecting unit 220. Also, the refrigerant expanded by the expansion unit 204 is prevented from flowing into the outside heat exchange unit 203 by the valve 221 of the connecting unit 220.

As descried above, the indoor space is heated and simultaneously frost formed on the outside heat exchange unit 203 can be removed (S14). Therefore, a heating operation does not need to be suspended to perform a separate defrosting operation.

In the above description, though an operation for removing frost formed on the outdoor heat exchange unit 203 is referred to as the defrosting operation, the front removing operation according to the present disclosure means an operation where a heating operation and a defrosting operation are performed simultaneously.

Whether a defrosting operation of the outdoor heat exchange unit 203 has been completed is judged (S26). At this point, when the temperature of the outdoor heat exchange unit 203 reaches a predetermined temperature, it is judged that the defrosting operation has been completed. When it is judged that the defrosting operation has been completed, a heating operation starts again (S21).

Referring to FIG. 6, when the heating operation is performed, refrigerant changes its phase while it passes through a process of {circle around (1)}→{circle around (2)}→{circle around (5)}→{circle around (6)}.

When the defrosting operation is performed, refrigerant that has flowed into the indoor heat exchange unit 205, of refrigerant that has passed through the compressor 201 is lowered in its temperature while it passes through a process of {circle around (2)}→{circle around (5)}. On the other hand, refrigerant bypassed by the bypass unit 210 passes through a process of {circle around (2)}→{circle around (3)} by the pressure controller 212, and is lowered in its pressure to the pressure at the entry of the outdoor heat exchange unit 203.

Also, the bypassed refrigerant passes through {circle around (3)}→{circle around (4)} while it passes through the outdoor heat exchange unit 203. Here, while the bypassed refrigerant passes through the outdoor heat exchange unit 203, the temperature of a pipe of the outdoor heat exchange unit 203 is raised. Also, frost on the outdoor heat exchange unit 203 is removed by the bypassed refrigerant.

Meanwhile, refrigerant that passes through the indoor heat exchange unit 205 undergoes a process of {circle around (5)}→{circle around (6)} while it passes through the expansion unit 204. Also, the bypassed refrigerant and the refrigerant that has passed through the expansion unit 204 merge at the exit of the outdoor heat exchange unit 203. In detail, during a refrigerant mixing process, refrigerant that has passed through the outdoor heat exchange unit 203 is lowered in its temperature while it undergoes a process of {circle around (4)}→{circle around (7)}, and refrigerant that has passed through the expansion unit 204 is raised in its temperature while it undergoes a process of {circle around (6)}→{circle around (7)}.

Meanwhile, the refrigerant that has merged at the exit of the outdoor heat exchange unit 203 flows into the accumulator 206, and is heated at the heating unit 207. That is, the mixed refrigerant is overheated inside the accumulator 207 to undergo a process of {circle around (7)}→{circle around (1)}. After that, the refrigerant is introduced to the entry of the compressing unit 201 by the switching unit 202.

As described above, frost formed on the outdoor heat exchange unit 203 can be removed without suspension of a heating operation. Therefore, the defrosting operation according to the present disclosure means a heating operation and a defrosting operation are performed simultaneously.

According to the present disclosure, a heating operation is performed even during a defrosting operation to reduce unpleasant feeling of a consumer, and reduce heating energy.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.

The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive.

One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the description.

The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments which fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.

Although the invention has been described with reference to several exemplary embodiments, it is understood that the words that have been used are words of description and illustration, rather than words of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified. Rather, the above-described embodiments should be construed broadly within the spirit and scope of the present invention as defined in the appended claims. Therefore, changes may be made within the metes and bounds of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the invention in its aspects. 

1. An air conditioning system, comprising: an indoor heat exchange unit which exchanges heat with indoor air; and an outdoor heat exchange unit which exchanges heat with outdoor air, wherein the outdoor heat exchange unit performs a defrosting operation to remove frost from the outdoor heat exchange unit while the indoor heat exchange unit simultaneously performs a heating operation to heat the indoor air.
 2. The air conditioning system according to claim 1, further comprising: a compressing unit that discharges high temperature refrigerant; a switching unit connected to a discharge side of the compressing unit, the outdoor heat exchange unit being connected to the switching unit; an expansion unit connected to the outdoor heat exchange unit, the indoor heat exchange unit being connected to the expansion unit and the switching unit; and a bypass unit that provides the high temperature refrigerant discharged from the compressing unit to an intake side of the outdoor heat exchange unit during the defrosting operation.
 3. The air conditioning system according to claim 2, wherein the bypass unit is connected to a refrigerant pipe between the compressing unit and the switching unit.
 4. The air conditioning system according to claim 2, wherein the bypass unit is connected to a refrigerant pipe between the switching unit and the indoor heat exchange unit.
 5. The air conditioning system according to claim 4, further comprising a connecting unit that provides refrigerant from a discharge side of the expansion unit to a discharge side of the outdoor heat exchange unit during the defrosting operation.
 6. The air conditioning system according to claim 2, wherein an accumulator comprising a heating unit is disposed at an intake side of the compressing unit.
 7. The air conditioning system according to claim 2, wherein the compressing unit comprises a plurality of compressors, and the bypass unit provides refrigerant discharged from at least one of the compressors to the intake side of the outdoor heat exchange unit during the defrosting operation.
 8. The air conditioning system according to claim 2, further comprising a refrigerant pipe connecting the compressing unit to the switching unit, the refrigerant pipe comprising a valve which is closed during the defrosting operation.
 9. The air conditioning system according to claim 2, wherein the bypass unit comprises a valve and a pressure controller.
 10. The air conditioning system according to claim 2, wherein a heating unit that heats refrigerant is disposed at an intake side of the compressing unit.
 11. An air conditioning system, comprising: a bypass unit that provides refrigerant discharged from a compressing unit to an intake side of an outdoor heat exchange unit during a defrosting operation; and a connecting unit that provides expanded refrigerant to a discharge side of the outdoor heat exchange unit during the defrosting operation.
 12. The air conditioning system according to claim 11, wherein the bypass unit is connected to a refrigerant pipe between a switching unit and an indoor heat exchange unit, and a refrigerant pipe between an expansion unit and the outdoor heat exchange unit.
 13. The air conditioning system according to claim 11, wherein the connecting unit is connected to a refrigerant pipe between an expansion unit and the outdoor heat exchange unit, and a refrigerant pipe between a switching unit and the outdoor heat exchange unit.
 14. The air conditioning system according to claim 11, wherein the connecting unit is connected to a refrigerant pipe between an expansion unit and the bypass unit.
 15. The air conditioning system according to claim 11, wherein a heating unit that heats refrigerant is disposed at an intake side of the compressing unit.
 16. A method for controlling an air conditioning system, comprising: performing heat exchange with indoor air to heat the indoor air; and simultaneously defrosting an outdoor heat exchange unit when a defrosting operation is triggered.
 17. The method according to claim 16, wherein defrosting the outdoor heat exchange unit comprises discharging refrigerant from a compressing unit, and providing a portion of the discharged refrigerant to an intake side of the outdoor heat exchange unit via a bypass unit.
 18. The method according to claim 17, further comprising heating refrigerant introduced to the compressing unit.
 19. The method according to claim 16, wherein the defrosting operation is triggered when the temperature of the outdoor heat exchange unit is less than a predetermined temperature.
 20. The method according to claim 16, wherein an indoor heat exchange unit performs the heat exchange with the indoor air, and refrigerant discharged from the indoor heat exchange unit is provided to a discharge side of the outdoor heat exchange unit via a connecting unit.
 21. The method according to claim 20, wherein refrigerant discharged from the indoor heat exchange unit is prevented from flowing into an intake side of the outdoor heat exchange unit. 